This invention relates generally to refrigeration systems using a multicomponent refrigerant fluid and is particularly useful for controlling the operation of a cryogenic liquefier.
The employment of multicomponent refrigerant fluids in the operation of refrigeration systems such as cryogenic liquefiers has recently been receiving increased attention. In any refrigeration system it is important to operate that system in its proper mode in the face of disturbances and numerous control systems for so operating refrigeration systems are known. In the case where the refrigerant fluid for a liquefier is a multicomponent refrigerant fluid it would be highly desirable to have a control system which does not rely on adjusting the refrigerant mixture online as such adjustment requires the addition of equipment that would add capital expense and add to the complexity of the operation.
Accordingly, it is an object of this invention to provide an improved apparatus for controlling the operation of a refrigeration system such as a cryogenic liquefier.
It is another object of this invention to provide an improved apparatus for controlling the operation of a refrigeration system such as a cryogenic liquefier which is particularly useful when the refrigerant fluid employed in the system is a multicomponent refrigerant fluid.
The above and other objects, which will become apparent to those skilled in the art upon a reading of this disclosure, are attained by the present invention which is:
Apparatus for producing refrigerated product comprising:
(A) a compressor, a surge tank, means for passing refrigerant fluid from the compressor to the surge tank said means including a surge tank inlet valve, and means for passing refrigerant fluid from the surge tank to the compressor said means including a surge tank outlet valve;
(B) a multistage heat exchanger having an initial stage and a final stage, and means for passing refrigerant fluid from the compressor to the heat exchanger said means including an aftercooler having a cooling fluid input valve;
(C) a phase separator having a vapor exit and a liquid exit, means for passing refrigerant fluid from the initial stage of the heat exchanger to the phase separator, and means for passing refrigerant fluid from the liquid exit of the phase separator to the compressor said means including a first Joule-Thomson valve;
(D) means for passing refrigerant fluid from the vapor exit of the phase separator to a second Joule-Thomson valve, from the second Joule-Thomson valve to the final stage of the heat exchanger, and from the final stage of the heat exchanger to the compressor;
(E) means for passing product fluid to the heat exchanger, and means for recovering refrigerated product from the heat exchanger said means including a product valve;
(F) a first controller for regulating the product fluid production rate, said first controller manipulating the compressor;
(G) a second controller for regulating the pressure of refrigerant fluid passed to the compressor, said second controller adjusting the position of the second Joule-Thomson valve;
(H) a third controller for regulating product fluid liquid level, said third controller manipulating the product valve;
(I) a fourth controller for regulating the temperature of the refrigerant fluid downstream of the aftercooler, the temperature of the refrigerant fluid upstream of the first Joule-Thomson valve and the liquid level in the separator, said fourth controller controlling the position of the cooling fluid input valve and also adjusting the position of the first Joule-Thomson valve; and
(J) a fifth controller for regulating the pressure of refrigerant fluid discharged from the compressor, said fifth controller adjusting the position of the surge tank inlet valve and also adjusting the position of the surge tank outlet valve.
As used herein the term xe2x80x9ccontrollerxe2x80x9d means a device that either directly manipulates or causes the manipulation of one or more pieces of plant equipment based on the value of one or more process measurements and the value of other inputs from either an operator or some other device.
As used herein the term xe2x80x9cJoule-Thomson valvexe2x80x9d means a valve that is used to provide cooling from the expansion of a gas.
As used herein the term xe2x80x9cphase separatorxe2x80x9d means a vessel wherein incoming fluid is separated into individual vapor and liquid fractions, typically by gravity.